Share-Based Compensation and Capital Stock Pre-Tax Stock-Based Compensation Expenses And Associated Income Tax Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	$ 3.1	$ 2.9	$ 7.9	$ 8.7
Income tax benefits	1.1	1.1	2.9	3.2
Stock Options [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	0.6	0.3	1.7	1.3
Restricted Stock [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	1.7	2.1	5.5	5.7
Performance Vested Restricted Stock Units [Member]
Share-Based Compensation and Capital Stock [Line Items]
Pretax share-based compensation expense	$ 0.8	$ 0.5	$ 0.7	$ 1.7